An earthen formation can include layers of media where elasticity of the media may be isotropic, anisotropic or isotropic in certain aspects and anisotropic in others. Such media may be characterized through seismic studies where, for example, elastic waves generated by a source travel through the media to be sensed by one or more sensors. Decisions based on such characterizations may involve expending considerable resources, for example, to extract oil, gas, etc. Various technologies, techniques, etc., described herein pertain to characterization of media.